Many transducer-array based systems, such as ultrasound imaging systems and including radar, sonar, optical, and audible sound systems and the like, use a remote module sometimes referred to as a probe. The probe typically houses an array of transducers and the system typically performs coherent signal processing. In the case of medical ultrasound, a user places the probe on the patient and the transducers emit energy (e.g., ultrasound waves) into the patient's body. The transducer array also receives energy that is reflected or echoed by the patient's body back to the transducers. The received echo waves are converted to electrical signals. The electrical signals are processed by the medical imaging system in order to create a visual representation of the targeted area inside the patient's body. Other non-medical uses of ultrasound include non-destructive testing of various materials.
Currently, medical imaging systems use typically large multi-conductor cables to carry the electrical signals from the probe to the system's main processing unit. Because of the large number of transducer elements typically required, a significant amount of energy is required to be carried by the cable. The relatively large cable creates difficulties electrically, medically, and physically.
From a physical perspective, for example, the cable is ergonomically burdensome. From an electrical perspective, the larger cable degrades the electrical interface to the main unit and adds capacitance to the system. By adding capacitance to the system, the impedance of the cable is significantly lower than the transducer array. As a result, the transducers may need to be powered with greater currents. Also, the cable capacitance may undesirably result in a lower signal-to-noise ratio (SNR).
From a medical perspective, the cable creates a problem where sterility is an issue. A probe used in a sterile field must either be sterilizable, or must be covered with a sterile sheath. With a cabled probe, the probe is covered with a sterile sheath that extends back over the cable, yet the covered cable eventually extends out of the sterile field because the main unit it not sterilizable. As the probe is used, the attached cable slides into and out of the sterile field. Once the cable slides out of the sterile field, the necessary sterility is compromised. As a result, a user is limited in using and moving the cabled probe.